To evaluate the toxicity of selected chemopreventive agents before human clinical trials, two species of experimental animals, are exposed to high doses of selected compounds. To determine agent toxicity acute toxicity, pilot dose rangefinding studies, 13 week chronic exposure, and pharmacology studies are being performed. The compounds being tested are calcium glucarate, difluoromethylornithine with retinol and piroxicam, and dehydroepiandosterone analogue 8354.